How to Use GNS3 in Windows

Many people want to use GNS3 to prepare for network professional exams. But most of the people face issue to use GNS3. In this post, we will explain how to use GNS3. To use GNS3, you need to create a network topology in GNS3 by adding routers and switches. Before you can use a device such as a router to create a network topology in GNS3, first, you need to add the Cisco IOS image for that device. You can freely download the GNS3 IOS images for the desired platform, such as a router, switch and PIX firewall.

Once you have downloaded the appropriate IOS image, you can add that IOS image in GNS3. In this post. we will explain the detailed steps how to add an IOS image for Cisco router in GNS3 and how to use GNS3. We assume that you have already downloaded the GNS3 tool and the few Cisco IOS images for GNS3. If you have not yet done it, please visit the following links.

So let’s begin how to add an IOS image in GNS3 and how to use GNS3. To add an IOS image for Cisco router in GNS3, you need to perform the following steps:

Open the GNS3 console, click Edit, and then select Preferences.

On the Preferences window, select IOS Routers in the left pane. Click New to add a new ISO image.

The New IOS Router template dialog box will be displayed.

Click Browse and select the IOS image that you want to add, and then click Next. In the following figure, we have used 2691 series IOS image.

On the Name and platform page, select the platform, (in this case, c2691), and then click Next.

On the Memory page, assign the desired memory size, we recommend to set it at least 128 MB, and then click Next.

On the Network adapter page, you can select the slots to add the additional interfaces.

On the WIC modules page, select a WAN Interface Card (WIC), and then click Next.

On the Idle-PC page, click Finish.

On the Preferences window, click Apply and then click OK.

On the GNS3 console, click the router icon, drag the router in the middle pane. Add one more router in the middle pane. Click the connection icon in the left lower corner. Click on R1 and select an interface such as FastEthernt0/0. Click on R2 and select the desired interface to connect R1 to R2.

On the GNS3 console, right-click on each router and select Start to start both the routers.

Once the routers are started, right-click on any router and select Console to open its console.

The router’s console will be displayed, as shown in the following figure.

Now, you can do on simulated Cisco IOS whatever you want to do on a physical Cisco router. That’s what GNS3 allows you.

In this post, we have discussed how to add Cisco IOS images in GNS3 and how to use GNS3. Hope you have enjoyed it. Let us know if you face any issue during adding the IOS images in GNS3.